Number of arranged elements 4 7 9 18 22 Symbol Number of arranged elements 29 34 37 53 83 04 07 09 18 22 29 34 37 53 83 Symbol Nominal filtration accuracy (m) Note) Nominal filtration accuracy (m) 0.5 1 2 5 10 20 40 Symbol Nominal filtration accuracy (m) 50 70 74 75 100 105 120 X50 001 002 005 010 020 040 050 070 074 075 100 105 120 Symbol Element length Element length L250 L500 (L250 x 2